Production of billet and extruded products from particulate materials

Abstract

Methods and apparatus are disclosed for consolidating loose or pre-compressed particulate materials, such as metal powder or metal flakes, in press equipment utilizing a reusable canister means that is sealed in vacuum from the atmosphere and heated prior to consolidation in the press equipment at elevated pressures and temperatures, thereby improving utilization of the press equipment.

I claim: 
     
       1. A method of consolidating particulate material into product of a density substantially equal to theoretical maximum density comprising the sequential steps of: a. loading loose or partially precompressed particulate material into a canister means having a tapered outer surface and closed and sealed lower extreme;   b. closing and sealing the upper extreme of said canister means with a closure and seal means;   c. heating said canister means and contained loaded material to an outgassing temperature while maintaining the interior of said canister means at a pressure significantly below atmospheric pressure;   d. heating or cooling said canister means and degassed particulate to a selected consolidation temperature, if different from the degassing temperature.   e. locating said heated canister means and degassed particulate material in a press receiver restraining ring means having an interior surface that is tapered to correspond to said canister means tapered outer surface;   f. shearing said upper closure and seal means and consolidating said particulate material at said consolidation temperature at a pressure which causes said heated particulate material to attain substantially 100% of theoretical maximum density;   g. ejecting said consolidated particulate material from within said canister means in unitary form; and   h. removing said canister means from within said press receiver restrainer ring.   
     
     
       2. The method of claim 1 wherein said canister means is forced into hoop compression by press-fitting the tapered outer surface of the canister means into the taper of the restraining ring means. 
     
     
       3. The method of claim 1 wherein said consolidated particulate material is ejected from within said canister means with a cross sectional area reduced from the cross sectional area of the interior of said canister means. 
     
     
       4. The method of claim 1 wherein the steps (a) through (h) are performed on a first material and repeated with said canister means using a second additional loose or pre-compressed particulate material following ejection of said the first material from within said canister means. 
     
     
       5. The method of claim 1 wherein said pre-compressed particulate material is pre-compressed to a density of from 70% to 85% of theoretical maximum density. 
     
     
       6. The method of claim 1 wherein said heating and outgassing step is accomplished while developing the interior of said canister means to a pressure of approximately 50 microns of mercury (Hg) or less. 
     
     
       7. The method of claim 1 wherein the shearing and pressing step f. is carried out by a press ram forcing a dummy block located below the sealing means, against the particulate material.